oh well..english is suppose to be simple language
No tool to migrate you 100% with no pains.
1) Create Exchange users - different passwors as youw will not (cannot) get the actaul password from Zimbra.
2) use ImapSync to migrate all emails
3) loose notes, calanders and stuff and be happy
or use Outlook PST import/export for each user.
other that above no other luck or tool i konw of